Optical fiber connection tool and optical fiber connection method

ABSTRACT

An optical fiber connecting tool is provided in which an optical fiber connecting tool  5  is used which has a ferule  7,  a connecting structure  10  which has two clamping sections  18, 19  which are disposed in a ferule  7.  A pre-installed optical fiber  6  and a newly installed optical fiber  17  are clamped in a butt-connected condition by a clamping section  18.  The newly installed optical fiber  17  is clamped by the other clamping section  19.  An optical fiber connecting tool  1  is provided which has an open/close member  2  which is detachably disposed on the clamping section  18  and another open/close member  3  which is detachably disposed on the another clamping section  19  such that the both of the open/close members  2, 3  can be operated independently. Also, a method for connecting optical fibers according to the present invention prevents an increase in a loss due to a bent optical fiber and a damage in the optical fiber by extracting the open/close member  2  from the clamping section  18  before extracting the open/close member  3  from the another clamping section and dispose a deformation which is generated on the tip section of the optical fiber when the optical fiber connecting part is attached on the tip section of the optical fiber according to steps for performing an extracting operation for the open/close member e from the another clamping section. Here, for the optical fiber connecting part, for example, various members can be adapted such as a member which does not have the above explained ferule, and a member which realize a connection and a clamping operation for the optical fibers by a structure of only the above explained connecting structure.

TECHNICAL FIELD

The present invention relates to an optical fiber connecting tool and amethod for connecting optical fibers. In particular, the presentinvention relates to an optical fiber connecting tools and a method forconnecting optical fibers which are effective for connecting thepre-installed optical fiber and the newly installed optical fiber to theoptical fiber connecting part by a connecting structure of the opticalfiber connecting part.

BACKGROUND ART

Recent year, an optical fiber connector which is provided with a ferulein which an optical fiber is inserted in a center of the ferule and aconnecting structure which is disposed in a tip section of the ferule isproposed for an optical fiber connector which can be attached to the tipsection of the optical fiber easily.

In such a case, the connecting structure is provided with a two-dividedconnecting elements which are formed by assembling two divided halvesand a clamping spring which engages to the outside of the connectingelement so as to compress both of the divided halves in its attachingdirection such that one of the divided halves is divided into two piecessuch as a main clamp and a substitute clamp and a groove is formed foran alignment on a attaching surface with the other one of the dividedhalves.

Consequently, in order to attach an optical fiber connector which has anabove explained structure to a tip of an optical fiber, for example, anoptical fiber connecting tool which has a pair of open/close member isused so as to insert both of the open/close members between the mainclamp and the other divided half, and between the substitute clamp andthe other divided halve. The clamping condition by both of the clamps isreleased by releasing the main clamp and the substitute clamp. The tipsection of the newly installed optical fiber is inserted between themain clamp and the other divided halve via the substitute clamp; thus,the tip of the newly installed optical is butt-connected to the tip ofthe pre-installed optical fiber in an inside of the main clamp indetail.

Consequently, both of the open/close members of the optical fiberconnecting tool is extracted from between the main clamp and the otherdivided half and from between the substitute clamp and the other dividedhalf simultaneously under such a condition. The pre-installed opticalfiber and the newly installed optical fiber are clamped under abutt-connected condition by the main clamp; thus, a section of the newlyinstalled optical fiber which is coated is clamped by the substituteclamp.

By doing this, it is possible to attach the optical fiber connector tothe tip section of the newly installed optical fiber such that thepre-installed optical fiber near the optical fiber connector and thenewly installed optical fiber are maintained under a butt-connectedcondition.

However, in the above explained optical fiber connecting tool, in a casein which the tip section of both of the optical fibers is deformed by abutt-connecting force of the newly installed optical fiber against thepre-installed optical fiber near the optical fiber connector, both ofthe optical fibers are clamped under such a deformed condition; thus,there are problems such as an increase in a loss due to a bent opticalfiber and a damage of the tip of the optical fiber which is caused by aconcentrated stress to the tip section of the both of the deformedoptical fibers; therefore, these problems may cause a defect connection.

DISCLOSURE OF INVENTION

The present invention was made in consideration of the above explainedconventional problems. An object of the present invention is to providean optical fiber connecting tool and a method for connecting opticalfibers in which it is possible to release the deformation which isgenerated on the tip section of at least the optical fiber by thebutt-connecting force between the optical fibers and prevent the defectconnection while avoiding the increase in a loss which is cause by abent optical fiber and a loss in the tip section of the optical fiber.

The present invention provides structures below for solving the aboveexplained problems.

In the present invention, an optical fiber connecting tool is providedwhich comprises one clamping section which clamps a periphery of abutt-connection section of an optical fiber which is butt-connected formaintaining a butt-connection condition, a base which supports anoptical fiber connecting part in which a connecting structure isdisposed which has another clamping section which clamps a new opticalfiber which is butt-connected to a pre-installed optical fiber which ispreviously inserted in the clamping section in the optical fiber, anopen/close member which is disposed in the clamping section so as to beable to open/close the another clamping section, and another open/closemember which is disposed so as to be inserted to/detached from theclamping section so as to be able to open/close the another clampingsection, wherein both of the open/close members can be operatedindependently.

According to the optical fiber connecting tool according to the presentinvention, an open/close member is inserted in one clamping section soas to open the clamping section. Other open/close member is inserted inthe another clamping section so as to open the another clamping section.In addition, the optical fiber is inserted in the connecting structureso as to butt-connect the optical fibers. In such a case, it isacceptable if the optical fiber may be inserted from both of facingsides of the connecting structure. Also, it is acceptable if there is arelationship such that either one of the optical fibers is apre-installed optical fiber which is inserted in the connectingstructure and the other one of optical fibers is a newly installedoptical fiber which is butt-connected to the pre-installed opticalfiber. In addition, either one of the open/close member is extractedfrom the clamping section and the clamping section is closed; thus theoptical fibers are clamped under the butt-connected condition. Inaddition, after that, the other open/close member is extracted from theanother clamping section, and the another clamping section is closed:thus, the optical fibers are clamped. By doing this, after closing theone clamping section, it is possible to maintain the connectingcondition by steps for closing the another clamping section while thereis few deformation in the optical fiber which is caused by thebutt-connecting force which is applied to the optical fiber. That is, itis possible to release the deformation in a direction of the opticalfiber before closing the other clamping section even if there is adeformation which is generated on the tip sections of the both of theoptical fibers due to the butt-connecting force of the optical fibers.Therefore, the tips of the both of the optical fibers are not clampedunder such a deformed condition. Also, the tip sections of the both ofthe optical fibers are not damaged due to the bent optical fibers and anincrease in the loss. Therefore, it is possible to restrict the defectconnection; thus, it is possible to enhance the reliability greatly.

Also, in the optical fiber connecting tool according to the presentinvention, it is possible to adapt a structure in which one of theoptical fibers which are butt-connected by the connecting structure is apre-installed optical fiber which is previously inserted in the clampingsection from one of the connecting structure by fixing in apredetermined position in the connecting structure by an optical fiberfixing section, another one of the optical fiber which is butt-connectedby the connecting structure is inserted in the clamping section viaanother clamping section from other side of the connecting structure soas to be a newly installed optical fiber which is butt-connected to theoptical fiber in the clamping section, the another clamping sectionclamps a section which protrudes from the clamping section for the newlyinstalled optical fiber which is clamped by the clamp. According to theoptical fiber connecting tool according to the present invention, anopen/close member is inserted in a clamping section so as to open theclamping section. Other open/close member is inserted in the otherclamping section so as to open the other clamping section. Theconnecting structure performs a butt-connecting operation for the tip ofthe pre-installed optical fiber which is disposed in the connectingstructure in advance to the tip of the newly installed optical fiber byinserting the newly installed optical fiber in the one clamping sectionvia another clamping section. In addition, either one of the open/closemember is extracted from the clamping section and the clamping sectionis closed; thus the pre-installed optical fiber and the newly-installedoptical fiber are clamped under the butt-connected condition. Inaddition, after that, the other open/close member is extracted from theother clamping section, and the other clamping section is closed: thus,the newly installed optical fiber is clamped. By doing this, it ispossible to connect the pre-installed optical fiber and thenewly-installed optical fiber without generating deformation. Therefore,it is possible to release the deformation in a direction of the newlyinstalled optical fiber before closing the other clamping section evenif there is a deformation which is generated on the tip sections of thenewly installed optical fiber against the pre-installed optical fiberdue to the butt-connecting force of the optical fibers. Therefore, thetips of the both of the optical fibers are not clamped under such adeformed condition. Also, the tip sections of the both of the opticalfibers are not damaged due to the bent optical fibers and an increase inthe loss. Therefore, it is possible to restrict the defect connection;thus, it is possible to enhance the reliability greatly.

Also, the present invention provides a method for connecting opticalfibers which uses a clamping section which clamps a periphery of abutt-connection section of an optical fiber which is butt-connected formaintaining a butt-connection condition, a base which supports anoptical fiber connecting part in which a connecting structure isdisposed which has another clamping section which clamps a new opticalfiber which is butt-connected to a pre-installed optical fiber which ispreviously inserted in the clamping section in the optical fiber, anopen/close member which is disposed in the clamping section so as to beable to open/close the another clamping section; and another open/closemember which is disposed so as to be inserted to/detached from theclamping section so as to be able to open/close the another clampingsection, wherein, a newly installed optical fiber is inserted into aclamping section, after that, a closing motion of the clamping sectionstarts, consequently, a closing motion of the other clamping sectionstarts. Such a method for connecting the optical fibers includes notonly a feature that the motion of the another clamping section isstarted after the one clamping section is closed but also a feature thatthe movement of the closing the another clamping section is started(before completing the clamping operation for the pre-installed opticalfiber and the newly installed optical fiber in the one clamping section)before completing the closing movement of the one clamping section.

Also, the present invention provides a method for connecting opticalfibers in which an optical fiber connecting tool is used which isprovided with a connecting structure which has a clamping section whichmaintains a butt-connecting condition by clamping a periphery of thebutt-connecting section which is butt-connected and another clampingsection which clamps a newly installed optical fiber which isbutt-connected to a pre-installed optical fiber which is previouslyinserted in the clamping section among the optical fibers, thepre-installed optical fiber which is contained in the connectingstructure in advance by the clamping section of the connecting structureand the newly installed optical fiber which is separate from thepre-installed optical fiber in a butt-connecting condition are clampedunder a butt-connection condition by the clamping section of theconnecting structure, the clamping section is opened by inserting theopen/close member which can be inserted into/detached from the clampingsection is inserted into the clamping section when the newly installedoptical fiber is clamped by the other clamping section of the connectingstructure, simultaneously, the other open/close member which can beinserted into/detached from the other clamping section is inserted intothe other clamping section so as to open the other clamping section,under this condition, the newly installed optical fiber is inserted fromthe other side so as to butt-connect the tip of the newly installedoptical fiber to the tip of the pre-installed optical fiber, under thiscondition, one of the open/close member is extracted from the clampingsection so as to clamp the pre-installed optical fiber and the newlyinstalled optical fiber by the clamping section under a butt-connectedcondition, consequently, the other open/close member is extracted fromthe other clamping section so as to clamp the newly installed opticalfiber by the other clamping section. According to a method forconnecting the optical fibers according to the present invention, anopen/close member is inserted in a clamping section so as to open theclamping section. Other open/close member is inserted in the otherclamping section so as to open the other clamping section. Consequently,the pre-installed optical fiber is inserted from one side of theconnecting structure under such a condition. The newly installed opticalfiber is inserted from the other side thereof. Thus, the tip of thenewly installed optical fiber is butt-connected to the tip of thepre-installed optical fiber. In addition, either one of the open/closemember is extracted from the clamping section and the clamping sectionis closed; thus the pre-installed optical fiber and the newly-installedoptical fiber are clamped under the butt-connected condition. Inaddition, after that, the other open/close member is extracted from theother clamping section, and the other clamping section is closed: thus,the newly installed optical fiber is clamped. By doing this, it ispossible to connect the pre-installed optical fiber and thenewly-installed optical fiber without generating deformation. Therefore,it is possible to release the deformation in a direction of the newlyinstalled optical fiber before closing the other clamping section evenif there is a deformation which is generated on the tip sections of thenewly installed optical fiber against the pre-installed optical fiberbecause the butt-connecting force of the optical fibers is too great.Therefore, the tips of the both of the optical fibers are not clampedunder such a deformed condition. Also, the tip sections of the both ofthe optical fibers are not damaged due to the bent optical fibers and anincrease in the loss. Therefore, it is possible to restrict the defectconnection; thus, it is possible to enhance the reliability greatly.

Here, this method for connecting the optical fibers can be used for anoperation for connecting the optical fibers in the connecting structureof the optical fiber connecting part by using the optical fiberconnecting tool according to the present invention.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A is an approximate plan view for showing a first embodiment ofthe optical fiber connecting tool according to the present invention.

FIG. 1B is a front view for showing an optical fiber connecting tool ofFIG. 1B.

FIG. 1C is a cross section for showing a section hear a guide groove ofthe optical fiber connection tool of FIG. 1A.

FIG. 2A is a plan vie for showing an example for an optical fiberconnector.

FIG. 2B is a side cross section for showing an inner structure of theoptical fiber connector shown in FIG. 2A.

FIG. 3 is a front view for showing an optical fiber connector shown inFIG. 2A.

FIG. 4 is a vertical cross section for showing an inner structure of theoptical fiber connector shown in FIG. 2A.

FIG. 5A is a dissembled isometric view for showing a structure for aferule with a connecting structure of the optical fiber connector shownin FIG. 2A.

FIG. 5B is a view in which a lid element which forms the connectingstructure of the ferule with a connecting structure shown in FIG. 5A isviewed from a direction which faces a base element.

FIG. 6 is a plan view for showing a condition in which the optical fiberconnector shown in FIG. 2 a is supported by the optical fiber connectingtool.

FIG. 7 is a front view for showing a structure for a ferule with aconnecting structure of the optical fiber connector shown in FIG. 2A.

FIG. 8 is a front view for showing a positional relationship between theferule with the connecting structure shown in FIG. 6 and the open/closemember of the optical fiber connecting tool.

FIG. 9 is a view for explaining a condition in which a first open/closemember is inserted in a first clamping section of the ferule with theconnecting structure and a second open/close member is inserted in asecond clamping section; thus, the first clamping section and the secondclamping section are open.

FIG. 10 is a view for explaining a condition in which a newly installedoptical fiber is inserted under condition the first clamping section andthe second clamping section are open; thus, the end surface of the newlyinstalled optical fiber is butt-connected to an end surface of thepre-installed optical fiber.

FIG. 11 is a view for explaining a condition in which the firstopen/close member is extracted from the first clamping section and thefirst clamping section is closed.

FIG. 12 is a view for explaining a condition in which the secondopen/close member is extracted from the second clamping section and thesecond clamping section is closed.

FIG. 13A is a plan view for showing other example for a ferule with theconnecting structure.

FIG. 13B is a front view for a ferule with the connecting structureshown in FIG. 13A.

FIG. 13C is a view in which the ferule with the connecting structureshown in FIG. 13A is viewed from a rear end section (an end sectionwhich is opposite to the end section which is connected to the ferule).

FIG. 14 is a plan view for showing a surface which faces to the lidelement of the base element which forms the connecting structure of theferule with the connecting structure shown in FIG. 13A.

FIG. 15 is an isometric view for showing an example for the opticalfiber connector which includes a built-in ferule with the connectingstructure shown in FIG. 13A.

FIG. 16 is an approximate plan view for showing a second embodiment ofthe present invention which shows an example for a case in which theoptical fiber connecting parts which forms a mechanical splice is usedfor the optical fiber connecting tool according to the presentinvention.

FIG. 17 is a front view for the optical fiber connecting part shown inFIG. 16.

FIG. 18A is a cross section for the optical fiber connecting part shownin FIG. 16 in which either one of the clamping sections which arelocated on both sides which faces to each other of the one clampingsection.

FIG. 18B is a cross section for showing the optical fiber connectingpart shown in FIG. 16 in which the one clamping section is shown.

FIG. 18C is a cross section for the optical fiber connecting part shownin FIG. 16 in which the other one of the clamping sections which arelocated on both sides which faces to each other (other clamping section)of the one clamping section.

FIG. 19 is an approximate plan view for showing a third embodiment ofthe optical fiber connecting tool according to the present invention.

FIG. 20 is a vertical cross section for showing an open/close member ofthe optical fiber connecting tool shown in FIG. 19.

FIG. 21A is a plan view for showing a condition in which an opticalfiber clamp is disposed in a separate position from aparts-containing-groove via a supporting bar which is attached to theoptical fiber connecting tool shown in FIG. 1A.

FIG. 21B is a side view for showing an optical fiber connector shown inFIG. 21A.

FIG. 22 is a dissembled plan view for showing a detaching structurebetween the optical fiber connecting tool and the supporting bar, and adetaching structure between the supporting bar and the optical fiberclamp.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention is explained in detail with reference to attacheddrawings.

Hereinafter, the embodiments of the present invention which are shown inthe drawings are explained.

FIGS. 1 to 15 show a first embodiment of the optical fiber connectingtool according to the present invention. This optical fiber connectingtool 1 can be applied effectively for a case in which the optical fiberconnecting part is attached to a tip section of the optical fiber. Asshown in FIGS. 1A and B, the optical fiber connecting tool 1 is providedwith a base 101 which fixes an optical fiber connecting part 5, and twoopen/clOse members 2, 3 which are disposed on the base 101.

The optical fiber connecting tool 1 according to the present inventioncan be applied for various type of optical fiber connecting tools 5.

The optical fiber connecting part 5 which is shown in FIG. 2A to FIG. 4contains a ferule 7 of an SC (SC; Single fiber coupling optical fiberconnector) optical connector which is defined by a JIS SC 5973 etc. in ahousing 502 (hereinafter, there are cases in which a reference numeral501 is added to the optical fiber connecting part for explanations).Furthermore, the optical fiber connecting part 5 contains a connectingstructure 10 (see FIG. 4 and FIG. 5) which are assembled in a rear endwhich faces an attaching end surface 8 of the tip of the ferule 7 in asleeve stop ring 503 which is connected to the housing 502. Hereinafter,this optical fiber connecting part is called an “optical fiberconnector”; thus, there is a case in which a reference numeral 501 isadded for an explanation. The connecting structure 10 has a structure inwhich it is assembled to a rear end of the ferule 7 such that the ferule7 and the connecting structure 10 are contained unitarily in inside ofthe housing 502 of the optical fiber connector 501 and inside of thestop ring 503 as a ferule 7A with a connecting structure. Also, as shownin FIG. 3, the optical fiber connector 501 can be connected detachablyto a female connector housing such as an optical connector adapter assimilar as an SC optical fiber connector by attaching it to a knob 508on an outside of the housing 502.

In FIG. 3 and FIG. 4, both the housing 502 and the stop ring 503 aresleeve members such that the ferule 7 of the ferule 7A with a connectingstructure is contained in the housing 502. The connecting structure 10of the ferule 7A with a connecting structure is contained in the stopring 503 which is assembled to a rear end (a right-hand side in FIG. 3and FIG. 4 for a viewer to the drawings) of the housing 502 by engagingthereto.

Here, in FIG. 3 and FIG. 4, the spring of the reference numeral 504compresses the ferule 7 a with a connecting structure in a direction foran attaching end surface 8 such as a direction for compressing an entireferule 7A with a connecting structure toward a tip of the housing 502 byusing a counter force of the stop ring 503. Here, a farther movement ofthe ferule 7A with a connecting structure toward the tip of the housing502 is regulated by contacting a flange section 9 of the ferule 7 at astopper wall 505 which is a small protrusion which is disposed in aninside of the housing 502. Also, a reference numeral 506 indicates aboot.

It is possible to insert the optical fiber into the optical fiberconnecting part 5 by the optical fiber connecting tool 1 such that theoptical fiber connecting part 5 should be contained so as to besupported by a groove 103 for containing a part which is formed so beconcave from an upper surface 102 of the base 101, the open/closemembers 2, 3 are driven, and these open/close members 2, 3 should becompressed in the optical fiber connecting part 5. After completing aconnecting operation for the optical fibers in the optical fiberconnecting part 5, the connecting condition for the optical fibers ismaintained because the optical fibers are clamped and supported by afunction of the optical fiber connecting part 5 by extracting theopen/close members 2, 3 from the optical fiber connecting part 3.

The groove 103 for containing part has a function for supporting theoptical fiber connecting part 5 by its inner shape stably. It issupposed to adapt a base 101 which has a groove 103 for containing apart which has a shape for supporting the optical fiber connecting part5 stably according to a shape of the optical, fiber connecting part 5.Also, in FIGS. 1A and B etc., a block 104 with a groove in which thegroove 103 for containing a part is exchangeably attached to the base101 such that it is possible to dispose the groove 103 for containing apart on the base 101 which correspond to a shape of the optical fiberconnecting part 5 by exchanging the block 104 with a groove. Forexample, it is possible to use the above explained ferule 7A with aconnecting groove in an independent manner as an optical fiberconnecting part. When the ferule 7A with a connecting structure isdisposed in the base 101, a base 101 (or a block 104 with a groove) isadapted which has a groove 103 for containing a part which has a shapeso as to be able to support the ferule 7A with a connecting structurestably. Here, the groove 103 for containing a part has a structure suchthat the optical fiber connecting part 5 can be contained/extracted fromabove the base 101. Such a base is not limited to a structure which hasa block with a groove which is exchangeable; thus, it is possible toadapt a structure in which a groove for containing a part is formed in abase directly.

The ferule 7A with a connecting structure of the above explained opticalfiber connector 501 is explained more specifically.

As shown in FIG. 4 and FIG. 5, an optical fiber 6 (a naked opticalfiber) is inserted (fixed) in a central section of the ferule 7). Insuch a case, an end of the optical fiber 6 is formed so as to correspondto an attached end surface of the ferule by a grinding operation; thus,the other end protrudes from a rear end surface 9 a of the ferule 7 by apredetermined length. The ferule 7 serves for a fixing section for anoptical fiber.

The connecting structure 10 is provided with a connecting element 11which is formed by a plastic member and a clamping spring 16 which isformed by a metal member which is engaged to an outside of theconnecting element 11.

The connecting element 11 has a divided structure in which a baseelement 12 which has an elongated shape which expands from the rear endsection of the ferule 7 and a lid element 13 which is a fracture of atip shape are assembled such that an end of the base element 12 isconnected/fixed to a flange section 9 of the ferule 7. The lid element13 is divided into two pieces such as a first lid element 14 which is alid element in an axial direction and a second lid element which isanother lid element such that the first lid element 14 should bedisposed nearer to the ferule 7 than the second lid element 15 so as tooverlap the base element 12. As shown in FIG. 5B, an groove foralignment 12 a which positions and aligns the optical fiber 17 which isbutt-connected to the optical fiber 6 near the ferule 7 is disposed on asurface which faces to the base element 12 of the first lid element 14very accurately (in the present embodiment, the optical fiber 17 is anoptical fiber core wire, in detail, the optical fiber 17 a which is anaked optical fiber which is exposed on a tip of the optical fiber 17 isconnected to the optical fiber 6 near the ferule. Such an groove foralignment 12 a has a V-shape in the present embodiment. In addition, itis possible to adapt shapes such as a U-shape, and a round shape (agroove which has a half-round shape in its cross section). Also, asshown in FIG. 5A, B, a grooves 12 b, 12 c for containing a coating whichcontains the optical fiber 17 which is inserted in the connectingstructure 10 from a rear end of the connecting structure 10 (a deepsection in right-hand of the drawing, a right-hand in FIG. 4) is formedon a surface which faces to the base element 12 of the second lidelement 15 and a surface which faces to the second lid element 15 of thebase element 12. In the connecting structure 10, the grooves forcontaining a coating 12 b, 12 c are grooves which have an enlarged shapefor the groove 12 a for alignment so as to be coincidentally in apositional relationship between the base element 12 and the second lidelement 15. In addition, the grooves 12 b, 12 c for containing a coatingare connected to the groove 12 a for alignment respectively undercondition that the connecting element 11 is closed (the lid element 13is attached to the base element 12). These grooves 12 b, 12 c forcontaining a coating also serves a guiding groove for introducing theoptical fiber 17 a (a naked optical fiber) of the tip of the opticalfiber 17 which is inserted into the connecting structure 10 from a rearend (a right-hand deep section in FIG. 5, a right-hand section in FIG.4) of the connecting structure 10. Here, cross sectional shapes of thegrooves 12 b, 12 c for containing a coating are not necessary to be thesame as the shape of the groove 12 a for alignment.

Here, it is acceptable as long as the groove for alignment may be formedat least on either the base element 12 or the first lid element 14.Also, it is acceptable if the groove for containing a coating may beformed only on either one of the base element or the lid element.

A clamping spring 16 which has a conduit cross section is engaged on anoutside of the base element 12 of the connecting element 11 and the lidelement 13 such that the base element 12 and the lid element 13 aremaintained under an attached condition by a compressing force of theclamping spring 16. An attaching section of the base element 12 and thelid element 13 is disposed in an aperture section of the clamping spring16. A notch section 16 a which is notched from an end surface of theaperture to a predetermined position is disposed in a central section ina longitudinal direction of the clamping spring 16 such that the firstlid element 14 is compressed at a section of the clamping spring 16which is disposed on a left-hand side of this notch section 16 a in adirection for the base element 12 and the second lid element 15 iscompressed at a right-hand side in a direction for a base element 12.

Here, as explained later, it is acceptable as long as the lid element 13has a structure in which a section (in other word, a section in which agroove for alignment is formed; one clamping section which is explainedlater) for clamping a connecting section in which an optical fibers 6and 17 are butt-connected and a section (in other word, a section inwhich a groove for containing a coating is formed; another clampingsection which is explained later) for containing and clamping a coatingsection of the optical fiber 17 are opened/closed byinserting/extracting the two open/close members 2, 3. From this point ofview, it is not limited necessarily to a structure in which they areseparate; that is, it is possible to adapt a structure in which they areformed unitarily. In case in which they are formed unitarily, forexample, it is possible to adapt a structure in which an openingoperation and a closing operation are realized separately. Also, it isacceptable as long as two clamping springs are opened/closed separatelydue to the same reason; that is, it is not necessary to adapt a clampingspring which has a notch section necessarily.

A shape of the clamping spring is not limited to a conduit crosssection; thus, it is acceptable if it has a C-letter shape crosssection.

The first clamping section 18 as one clamping section is formed by thefirst lid element 14, a section of the base element 12 which correspondsthereto, and a left-hand section of the clamping spring 16 which isengaged to thereoutside such that the second clamping section 19 asanother clamping section is formed by a second lid element 15, a sectionof a base element 12 which corresponds thereto, and a right-hand sectionof the clamping spring 16 which is engaged to thereoutside.

As shown in FIG. 1, the optical fiber connecting tool 1 is provided witha base 101 which fixes the optical fiber connector 5, a first open/closemember 2 which is an open/close member which can move forwardly andbackwardly in a direction of the optical fiber connector 5 which isdisposed and fixed on the base 101, and a second open/close member 3which is another open/close member such that both of the open/closemembers 2, 3 can be operated independently respectively.

As shown in FIG. 3 and FIG. 4, the tip sections of the first open/closemember 1 and the second open/close member 3 are formed in a wedge shaperespectively such that the tip section of the first open/close member 2can be inserted/extracted between the first lid element 14 and the baseelement 12 and the tip section of the second open/close member 3 can beinserted/extracted between the second lid element 15 and the baseelement 12.

The first open/close member 2 and the second open/close member 3 areattached on a driving structure (not shown in the drawings) so as tomove forwardly and backwardly in a direction of the optical fiberconnector 5 on the base 101 by operating the driving structure independently. In such a case, it is acceptable if the driving structuremay be operated manually and the driving structure may operatedautomatically by using a dynamic force.

The optical fiber connecting tool 1 which is shown in FIGS. 1A, B have astructure in which the open/close members 2, 3 are operated manually.The open/close members 2, 3 are members which have narrow long shapessuch that, as shown in FIGS. 1A to C, a longitudinal direction centralsection is contained in a guide groove 106 which is secured between thebase 101 and a push plate 105 which is attached on the base 101. Theseopen/close members 2, 3 can move forwardly and backwardly toward thegroove 103 for containing a part by performing a sliding movementagainst a base 101 and a push plate 105 by sliding on an inner surfaceof the guide groove 106. Here, a position shift of the open/closemembers 2, 3 are prevented except a forward/backward direction towardthe groove 103 for containing a part due to an accuracy for forming aninner surface of the guide groove 106. Although the wedge sections ofthe tip sections of the open/close members 2, 3 are disposed so as to benearer to the groove 103 for containing a part than the guide groove106, it is acceptable if the wedge sections of the tips of theopen/close members 2, 3 may be drawn in the guide groove 106 by abackward motion of the open/close members 2, 3 (a movement in adirection away from the groove for containing a part).

An operating fracture 107 is attached to the tip sections of theopen/close members 2, 3. The tip sections of the open/close members 2, 3which are protruded opposite to the groove 103 for containing a partfrom the guide groove 106 are sections which have a function for ahandle for operating the open/close members 2, 3 manually. Also, awindow 108 which is formed on a push plate 105 serves for a purpose inwhich a mark which is formed by a coloring operation or making aconcavo/convex sections on the open/close members 2, 3 should beobserved visually from an outside of the optical fiber connecting tool1. In the present embodiment, the window 108 and the mark serve forfunctions as follows. That is, when the mark can be observed from thewindows 108, it indicates that the tips of the open/close members 2, 3protrude at a containing position for the optical fiber connecting part5 in the groove 103 for containing a part; therefore, there is apossibility in that a containing operation and an extracting operationfor the optical fiber connecting part 5 for the groove 103 forcontaining a part may be disturbed (prohibition for a containingoperation and an extracting operation). If the mark is invisible bymoving the open/close members 2, 3 in a backward direction (a left-handside in FIGS. 1A, B) from the groove 103 for containing a part, itindicates that it is possible to contain/extract the optical fiberconnecting part 5 for the groove 103 for containing a part. Functions ofthe mark which is observed from the window 108 is not limited to such acase. For example, it is acceptable to realize functions such that, ifthe mark is not visible, it is indicates that it is possible tocontain/extract the optical fiber connecting part 5 for the groove 103for containing a part, and if the mark is visible, it indicates aprohibition for containing/extracting therefore.

Here, for example, a stopper (not shown in the drawings) for setting alimit for a movement in a forward direction (compressing direction)toward the groove for containing a part of the open/close members 2, 3by a protrusion etc. which is protruded from the push plate 105 and aprotrusion etc. which is protruded from the base 101 are disposed in theguide groove. Furthermore, it is possible to adapt a structure in whichan above explained stopper is formed to be a block with a groove suchthat a limit for moving the open/close members 2, 3 in a forwarddirection so as to correspond to a structure of the optical fiberconnecting part which is contained in the block with a groove; thus, theoptical fiber connecting part should not be damaged by an excessivecompression of the open/close members 2, 3.

In order to attach the optical fiber connecter 501 to a tip section of anewly installed optical fiber 17 by using the optical fiber connectingtool 1 according to the present embodiment which has the abovestructure, first, as shown in FIGS. 6 to 11 (here, the housing of theoptical fiber connector and the stop ring are omitted in the drawings,and a relationship between the ferule 7A with a connecting structure andopen/close members 2, 3 is shown clearly), the optical fiber connector501 is fixed on the base 101 (see FIGS. 1A, B), next, the firstopen/close member 2 and the second open/close member 3 are moved in adirection of the optical fiber connector 501. The first open/closemember 2 and the second open/close member 3 are inserted into wedgeinserting holes 507 a, 507 b (see FIG. 3) which are formed as apertureson a side sections of the stop ring 503 of the optical fiber connector501. The tip section of the first open/close member 2 is inserted so asto cut inbetween the first lid element 14 of the connecting element 11and the base element 12 so as to resist to a compressing force of theclamping spring 16 from the wedge inserting hole 507 b. The first lidelement 14 is opened such that the tip section of the second open/closemember 3 is inserted so as to cut inbetween the second lid element 15and the base element 12 so as to resist to a compressing force of theclamping spring 16 from the wedge inserting hole 507 b. The second lidelement 15 is opened (see FIG. 9). Here, although FIG. 9 shows acondition in which another clamping section 19 is opened by insertingthe open/close member 3, it is certain that it is not necessary to saythat one clamping section 18 is opened by inserting the open/closemember 2 as similar as a case of FIG. 9.

In addition, the tip section of the newly installed optical fiber 17 isinserted from another end (rear end) of the connecting element 11 alongthe groove for alignment 12 a so as to be butt-connected to the tip ofthe pre-installed optical fiber 6. The optical fiber 6 near the ferule 7is inserted so as to be fixed in a fine pour which penetrates the ferule7 along a center axial line of the ferule 7 in advance. A protruding tipof the ferule 7 is inserted between the base element 12 of theconnecting element 11 and the first lid element 13 from an end of theconnecting element 11. More specifically, the newly installed opticalfiber 17 butt-connects the optical fiber 17 a (here, a naked opticalfiber) of the tip to the optical fiber 6 which is protruded at theconnecting structure 10 from a rear end of the ferule. In addition, bothof the optical fibers 6, 17 a are butt-connected at a center section ina longitudinal direction of the groove 12 a for alignment. Theconnection is realized by the groove 12 a for alignment under accuratelypositioned and aligned condition each other. The condition for aligningthe optical fibers 6, 17 a is maintained after (explained later) closingthe connecting element 11 of the connecting structure 10.

In addition, as shown in FIG. 11, the newly installed optical fiber 17is compressed in a direction of the pre-installed optical fiber 6 by apredetermined force; thus, the butt-connecting force between the opticalfibers 6, 17 a is maintained. While maintaining such a condition, thefirst open/close member 2 is extracted from between the first lidelement 14 and the base element 12 by activating the driving structureso as to close the first lid element 14 by a compressing force of theclamping spring 16. The tip section of the optical fiber 6 and the tipsection of the newly installed optical fiber 17 are clamped between thefirst lid element 14 and the base element 12. The tip sections of bothof the optical fibers 6, 17 are maintained under a butt-connectedcondition. Here, even if the optical fibers 6, 17 a are not contacted bya refractive index rectifying agent etc. which is injected in theconnecting structure 10, in case in which the optical fibers 6, 17 canbe connected sufficiently (there is a case in which an opticalconnection is possible even if there is a slight interval between theoptical fibers 6, 17 by a function of the refractive index rectifyingagent), it is not necessarily necessary that the butt-connecting forceshould be applied continuously when one clamp section is closed. It isacceptable if one clamping section is closed under condition that thebutt-connecting force is not applied. Even for such a case, it ispossible to prevent from applying an unnecessary deformation and bendingstress to the optical fiber easily and reliably by steps for closinganother clamping section after closing one clamping section. By doingthis, it is possible to maintain an optical characteristics for theoptical fibers (in particular, a newly installed optical fiber) andrealize an improved reliability for a connection between both of theoptical fibers. Such a condition can be applied to a case for aconnection between the optical fibers in a connecting structure (inparticular, in one clamping section) in other embodiments of the presentinvention.

Next, as shown in FIG. 12, the second open/close member 3 is extractedfrom between the second lid element 15 and the base element 12 byactivating the driving structure. The second lid element 15 is closed bya compressing force of the clamping spring 16. Thus, the coating sectionof the newly installed optical fiber 17 such as the other clampingsection 19 is clamped between the second lid element and the baseelement 12. When the other clamping section 19 is closed, thebutt-connecting force of the optical fiber 17 which faces the opticalfiber 6 is released before the optical fiber 17 is clamped by theclamping section 19. Such a feature can be applied to the otherembodiments of the present invention commonly when the other clampingsection is closed after closing one clamping section.

By doing this, it is possible to attach the optical fiber connector 5 tothe tip section of the optical fiber 17; thus, it is possible tomaintain a butt-connected condition between the pre-installed opticalfiber 6 of the optical fiber connector 5 and the newly installed opticalfiber 17.

According to an optical fiber connecting tool 1 according to the presentembodiment which has the above explained structure and a method forconnecting the optical fibers, the first open/close member 2 and thesecond open/close member 3 are operated independently; thus, the firstopen/close member 2 is extracted so as to close the first lid element14. After this, the second open/close member 3 is extracted so as toclose the second lid element 15. According to such a structure, in acase in which the newly installed optical fiber 17 is butt-connected tothe tip of the pre-installed optical fiber 6, the second lid element 15is under opened condition even if there is a deformation on the tipsection of the optical fiber 17 or on the tip sections of the both ofthe optical fibers 6, 17 against the optical fiber 6 by thebutt-connecting force between the both of the optical fibers. Therefore,it is possible to release such a deformation in a direction of the newlyinstalled optical fiber 17; thus, the second lid element 15 is closedafter completely (or entirely) removing the deformation.

Therefore, it does not occur that the both of the optical fibers 6, 17are clamped under condition that the deformation is kept generated onthe tip sections of the both of the optical fibers 6, 17; thus, lossincreases because the optical fibers 6, 17 are bent or the opticalfibers 6, 17 may be damaged because the stress is applied on the tipsections for the both of the optical fibers 6, 17 collectively. Thus, itis possible to restrict the defect connection; therefore, it is possibleto enhance the reliability greatly.

Furthermore, it is possible to design the first open/close member 2 andthe second open/close member 3 separately; thus, it is possible torealize a low cost operation. That is, although the open/close members2, 3 are adapted which correspond to one clamping section and theanother clamping section which are designed respectively (for example,the size of a full aperture of the first lid element 14 of the firstclamping section 18 is different from the size of the full aperture ofthe second lid element 15 of the second clamping section 19), either ofthem are required to be produced by a very high accuracy so as tocorrespond to the design for the clamping section which is supposed tobe an object to be applied. If it is supposed to form a wedge protrusionwhich is inserted/extracted in the first clamping section 18 and a wedgeprotrusion which is inserted/extracted in the second clamping section 19in one member, it is necessary to perform a precise forming operation ina plurality of sections in one member. In addition, there may occur anecessity for securing a positional relationship between the wedgeprotrusions accurately; therefore, it is difficult to secure theaccuracy and time and labor need to take, and it is difficult to realizea low cost operation. It is possible to manufacture easily and realize alow cost operation by designing the first open/close member 2 and thesecond open/close member 3 separately.

Here, in the above embodiments, an optical fiber connecting toolaccording to the present invention is adapted for a single core opticalfiber connector 5. Although it is not shown in the drawings, it iscertain that similar operation and effect can be realized even if theoptical fiber connecting tool according to the present invention isadapted to a multi-core optical fiber connector. Also, in the presentembodiment, although two clamping sections are disposed, it is possibleto adapt a member in which more than two clamping sections are disposed.

For examples for optical fiber connecting parts 5 to which it ispossible to adapt the present invention, although it is not limited tothe above explained optical fiber connector 501, it is possible to adaptvarious structures such as a ferule 71 a with a connecting structureshown in FIG. 13A to C, and FIG. 14 and a mechanical splice (opticalfiber connecting part 20) shown in FIG. 16 to FIG. 18.

Here, the ferule 71A with a connecting structure is built in a housing511 of the optical fiber connector 510 shown in FIG. 15. The opticalfiber connector 510 is so called an MTRJ optical connector in which alatch 512 is disposed so as to protrude on an outside of the housing 511and detachably engage the connector housing such as an optical connectoradapter such that the connecting condition is maintained by anengagement of the latch when it is inserted in the connector housing andthe engagement to the connector housing can be released by operating thelatch 512.

In the ferule 71A which is shown in FIGS. 13A to C, and FIG. 14, theconnecting structure 110 is assembled to a rear end which faces near theconnecting end surface 81 (near the tip end). The ferule 71 is definedto be so called an MT optical connector (JIS C 5981, IEC 1754-5 etc.,MT; Mechanically Transfearable); thus, it is made of a plastic member.In the ferule 71, a plurality (two pieces in an example shown in thedrawings) of optical fibers 61 are inserted so as to be fixed, and thetips of each optical fiber 61 is exposed in an attaching end surface 81.The ferule 71 serves for a fixing section for an optical fiber.

The connecting structure 110 is provided with a connecting element 111which is formed by a plastic member which is disposed in a rear end ofthe ferule 71 and a clamping spring 116 which is formed by a metalmember which is engaged to an outside of the connecting element 111.

The connecting element 111 has a divided structure in which a baseelement 112 which has an elongated shape which expands from the rear endsection of the ferule 71 and a lid element 113 which is a fracture of atip shape are assembled such that an end of the base element 112 isconnected/fixed to a rear end section of the ferule 71. The lid element113 is divided into two members such as a first lid element 114 as a lidelement in an axial direction and a second lid element as the other lidelement. Also, the optical bier 61 near ferule has a protruding sectionwhich protrudes from a rear end section of the ferule 71. Thisprotruding part is disposed between the base element 112 and the firstlid element 114. As shown in FIG. 14, an groove for alignment 112 awhich positions and aligns the optical fiber 171 which is butt-connectedto the optical fiber 61 is disposed on a surface which faces to thefirst lid element 114 of the base element 112 very accurately (in thepresent embodiment, the optical fiber 171 is a single core optical fibercore wire, in detail, the optical fiber 171 a which is exposed on thetip of the optical fiber 171 is connected to the optical fiber 61 nearthe ferule). Such an groove for alignment 112 a has a V-shape in thepresent embodiment. In addition, it is possible to adapt shapes such asa U-shape, and a round shape (a groove which has a half-round shape inits cross section). Also, a grooves 112 b, 112 c (see FIG. 13C) forcontaining an optical fiber 171 (in detail, a coating section in whichthe optical fiber 17 a is not exposed) which is inserted in theconnecting structure 110 from a rear end of the connecting structure 110(a right-hand side in FIG. 13) is formed on a surface which faces to thebase element 112 of the second lid element 115 and a surface which facesto the second lid element 115 of the base element 112. In the connectingstructure 110, the grooves 112 b, 112 c for containing a coating form ahole which has a rectangular cross shape when an interval between thebase element 112 and the second lid element 115. The grooves 112 b, 112c for containing a coating clamp so called an optical fiber tape corewire so as to support therefore stably without a movable clearance whenan interval between the base element 112 and the second lid element 115is closed. A plurality of introducing grooves 112 d which are continuousfrom the groove 112 a for alignment are formed in parallel on a bottomsection of the groove 112 c for containing a coating of the base element112. The introducing groove 112 d has a function for introducing theoptical fiber 171 a (a naked optical fiber) on the tip of the opticalfiber 171 which is inserted into the connecting structure 110 from arear end of the connecting structure 110 to the groove 112 a foralignment. Here, cross sectional shapes of the introducing grooves 112 dfor containing a coating is not necessary to be the same as the shape ofthe groove 112 a for alignment.

Here, it is acceptable as long as the groove for alignment may be formedat least on either the base element 112 or the first lid element 114.

A clamping spring 116 which has a conduit cross section is engaged on anoutside of the base element 112 of the connecting element 111 and thelid element 113 such that the base element 112 and the lid element 113are maintained under an attached condition by a compressing force of theclamping spring 116. An attaching section of the base element 112 andthe lid element 113 is disposed in an aperture section of the clampingspring 116. A notch section 116 a which is notched from an end surfaceof the aperture to a predetermined position is disposed in a centralsection in a longitudinal direction of the clamping spring 116 such thatthe first lid element 114 is compressed at a section of the clampingspring 116 which is disposed on a left-hand side of this notch section116 a in a direction for the base element 112 and the second lid element115 is compressed at a right-hand side in a direction for a base element112.

Here, as explained later, it is acceptable as long as the lid element113 has a structure in which a section (in other word, a section inwhich a groove for alignment is formed) for clamping a connectingsection in which an optical fibers 61 and 171 are butt-connected and asection (in other word, a section in which a groove for containing acoating is formed) for containing and clamping a coating section of theoptical fiber 171 are opened/closed by inserting/extracting the twoopen/close members 2, 3. From this point of view, it is not limitednecessarily to a structure in which they are separate; that is, it ispossible to adapt a structure in which they are formed unitarily. Incase in which they are formed unitarily, for example, it is possible toadapt a structure in which an opening operation and a closing operationare realized separately. Also, it is acceptable as long as two clampingsprings are opened/closed separately due to the same reason; that is, itis not necessary to adapt a clamping spring which has a notch sectionnecessarily.

A shape of the clamping spring is not limited to a conduit crosssection; thus, it is acceptable if it has a C-letter shape crosssection.

The first clamping section 118 as one clamping section is formed by thefirst lid element 114 which is disposed nearer to the ferule than thesecond lid element 115, a section of the base element 112 whichcorresponds to it, and a left-hand section of the clamping spring 116which is engaged to an outside of them. The second clamping section 119which is the other clamping section is formed by a second lid element115, a section of the base element 112 which corresponds to it, and aright-hand section of the clamping spring 116 which is engaged to anoutside of them. Also, it is possible to perform a connecting operationfor the optical fibers to this optical fiber connecting part 71A assimilarly to a case of the above explained optical fiber connecting part501 by using the optical fiber connecting tool according to the presentinvention. Here, it is possible to handle the optical fiber connector502 which is formed by assembling the ferule 71A with the connectingstructure as an optical fiber connecting tool in which it is possible toperform a connecting operation for the optical fibers by using theoptical fiber connecting tool according to the present invention byopening a hole for inserting a wedge thereinto for inserting theopen/close members 2, 3 in a section near the housing 511.

In a case in which the newly installed optical fiber which isbutt-connected to the pre-installed optical fiber 61 which is an opticalfiber 61 near the ferule in the connecting structure 110 is an opticalfiber tape core wire, the optical fiber (optical fiber tape core wire)is inserted in the connecting structure 110 which is opened by theoptical fiber connecting tool 1. Consequently, in order to connect it tothe optical fiber 61 of the ferule 71, each of a plurality (the samenumber as the quantity for the grooves 112 a for alignment) of nakedoptical fibers which are exposed thereat is inserted into theintroducing grooves 112 d respectively on a bottom section of thegrooves 112 c for containing a coating of the base element 112.Consequently, it is possible to insert each of the naked optical fiberinto the groove 112 a for alignment by compressing the optical fibertoward the ferule 71. Also, the coating section of the optical fiber(optical fiber tape core wire) is contained in the grooves 112 b, 112 cfor containing a coating. According to a method for connecting opticalfibers according to the present invention, while maintaining aconnecting condition of the naked optical fiber of the optical fibertape core wire and the optical fiber 61 near the ferule, the connectingstructure 110 (more specifically, a connecting element 111) is closed byextracting the open/close members 2, 3. Consequently, the optical fibersare clamped so as to be supported in the first clamping section 118while the butt-connecting condition for the optical fibers ismaintained. Next, the coating section of the optical fiber (opticalfiber tape core wire) is clamped so as to be supported in the secondclamping section 119. As similarly to a case of the above explainedoptical fiber connecting part 501, it is possible to realize a clampingand supporting operation for the optical fibers under condition that anunnecessary bending of the optical fibers are solved.

For a case of the ferule 71A with the connecting structure, it ispossible to connect the optical fiber 61 near the ferule 71 to theconnecting structure 110 by inserting a single core optical fiber suchas a single core optical fiber core wire. Also, if a connecting element111 of the connecting structure 110 is closed by extracting theopen/close members 2, 3 according to a method for connecting opticalfibers according to the present invention, it is possible to maintain aconnecting condition for the optical fibers. It is possible to clamp andsupport a single core optical fiber to the second clamping section 119.For such a case, it is possible to insert the single core optical fiberone by one into the grooves 112 a for alignment from the grooves 112 b,112 c for containing a coating so as to feed thereinto. In a case of thesingle optical fiber, the naked optical fiber of which coating on itstip is removed is inserted into the groove 112 a for alignment.

Here, the above explained ferule 71A with the connecting structure has astructure which uses a multi-core ferule 71. For such an optical fiberconnecting tool according to the present invention, for example, it ispossible to adapt a single core member as a ferule which is an MToptical connector. For a connecting structure, it is possible to adapt astructure which adapts a member in which a single member such as agroove for alignment and only one piece of groove for containing acoating is formed.

FIGS. 21A to C, FIG. 22 show a case in which an optical fiber clamp 201is attached to the optical fiber connecting part 1. As shown in FIG.21C, the optical fiber clamp 201 has a structure in which a flexiblemember 202 is supported on a frame body 203. This optical fiber clamp201 is disposed from a distant position (for example, several tens mm toseveral hundreds mm) from the base 101 by attaching it to a supportingbar 204 which is fixed on a side section of the base 101 of the opticalfiber connecting part 1. The supporting bar 204 is attached detachablyon the base 101 by inserting and engage an engaging pin 204 a which isprotruded on an end in a longitudinal direction on an engaging hole 109a which opens an aperture on a side surface of the 101, and by furtherabsorbing magnetically a magnet 204 b which is fixed on an end in thelongitudinal direction on a magnet 109 b which is disposed on a base101. The optical fiber clamp 201 is detachably attached to another endsection in a longitudinal direction of the supporting bar 204 byengaging the engaging pin 205 which protrudes near the frame body 203 inan engaging hole 204 c which has an aperture on the other end section inthe longitudinal direction of the supporting bar 204. Here, thestructure for attaching the one end in the longitudinal direction of thesupporting bar 204 on the base 101 and the structure for detachablyattaching the optical fiber clamp 201 on the another end of thelongitudinal direction of the supporting bar 204 are not limited to theabove explained structures; thus, various structures can be adapted.Also, it is possible to adapt a structure in which a part in which asupporting bar and an optical fiber clamp are unified is detachablyattached to the base 101.

The optical fiber clamp 201 is a member which can support an opticalfiber easily only by compressing an optical fiber which is supposed tobe inserted into an optical fiber connecting part 5 which is engaged ina groove 103 for containing a part of the optical fiber connecting toolinto a slit 206 which is formed on a flexible member 202. The aboveexplained slit 206 has a shape which is cut from a side of a sectionwhich is exposed from the frame member 203 of the flexible member 202.Also, it is possible to extract an optical fiber which is inserted inthe slit 206 from the slit easily.

If the optical fiber connecting part 5 is an optical fiber connectorsuch as above explained ferules 7A, 71A with a connecting structure, andan optical fiber connector in which the the ferules 7A, 71A with such aconnecting structure are assembled, the optical fiber connecting part 5which is contained in the groove 103 for containing a part is supportedon the base 101 in the ferule and the connecting structure such that theconnecting structure should be disposed toward the optical fiber clamp201 against the ferule. For example, the optical fiber which iscompleted to be inserted into the optical fiber connecting part 5 in thegroove 103 for containing a part is clamped and supported by the opticalfiber clamp 201, the deformation of the optical fiber is secured betweenthe optical fiber connecting part 5 and the optical fiber clamp 201;thus, it is possible to use for securing a compressing force for theoptical fiber into the optical fiber connecting part 5 by utilizing arigidity of the optical fiber which tends to recover to be in a linearmanner. Also, as shown in FIG. 21, if a plurality of slits 206 areformed in the flexible member 202, it is possible to use this opticalfiber 201 for holding the optical fiber tentatively in an operation forconnecting it to the optical fiber near the ferule 71 by inserting aplurality of optical fibers (for example, a single core optical fiber)into the ferule 71A with the connecting structure.

Also, for other examples for the structure, it is possible to adapt astructure in which the above explained supporting bar 204 is a guidemember which supports the optical fiber holder slidably which supportsthe optical fiber in a direction forwardly and backwardly with referenceto a supporting position of the optical fiber connecting part in thebase 101.

For the optical fiber connecting tool according to the presentinvention, a member in which the above explained supporting bar 204 isattached on the base 101 and the member in which the optical fiber clamp201 is further attached thereto are included.

An optical fiber connecting part 20 which is shown in FIG. 16 to FIGS.18A to C is formed for a single core mechanical splice of which basicstructure is similar to that in the first embodiment. Here, it ispossible to realize a multi-core function in this optical fiberconnecting part 20 by forming a plurality of grooves 32 a for alignmentwhich is explained later and grooves 32 b, 32 c for containing a coatinghorizontally.

That is, the optical fiber connecting part 20 is formed only by theconnecting structure 30. The optical fiber connecting part 20 isprovided with a connecting element 31 which is formed by a plasticmember etc., and a clamping spring 37 which is formed by a metal memberwhich is engaged to an outside of the connecting element 31.

The connecting element 31 has a divided structure in which a prismaticbase element 32 and a prismatic lid element 33 are assembled such thatthe lid element 33 is divided into three members such as a first lidelement in an axial direction, a second lid element 35, and a third lidelement 36. The groove 32 a for alignment is disposed on a surface whichfaces to the second lid element 35 of the base element 12 such that itis possible to align an optical fiber 40 to the another optical fiber 41by this groove 32 a for alignment accurately. Grooves 32 b, 32 c forcontaining a coating for containing a coating section of the opticalfibers 40, 41 are formed on a surface which face the first lid element34 and the second lid element 36 of the base element 12 so as to becontinuous from the groove 32 a for alignment. These grooves 32 b, 32 cfor containing a coating are grooves of which aligning accuracy is lowerthan that of the groove 32 a for alignment. These grooves 32 b, 32 c forcontaining a coating have function as an introducing groove forintroducing the optical fibers 40, 41 which are inserted into theconnecting structure 30 from an outside of the optical fiber connectingpart to the groove 32 a for alignment. Although, in the example shown inthe drawings, the groove 32 a for alignment and the grooves 32 b, 32 cfor containing a coating are V-grooves, it is not limited to thesestructure; thus, it is possible to adapt various shapes. Also, theoptical fibers 40, 41 are optical fiber core wires in the presentembodiment. Naked optical fibers 40 a, 41 a which are exposed on thetips of the optical fibers 40, 41 are inserted into the groove 32 a foralignment so as to be butt-connected. The position for forming thegrooves for containing a coating may be on a surface which faces to thebase element 12 of the first lid element 34 and the second lid element36. Also, it is possible to form the grooves for containing a coating onboth a surface which faces to the first lid element 34 and the secondlid element 36 of the base element 12 and a surface which faces to thebase element 12 of the first lid element 34 and the second lid element36. The groove for alignment is not limited to the base element; thus,it is possible to form the groove for alignment on the lid element, alsoon both of the lid element and the base element.

The clamping spring 37 which has a conduit shape cross section with asimilar structure to a member which is shown in the first embodiment isengaged to an outside of the base element 32 of the connecting element31 and the lid element 33 such that the base element 32 and the lidelement 33 are supported so as to be under an attached condition by acompressing force of this clamping spring 37. In such a case, a sectionin which the base element 32 and the lid element 33 are attached ispositioned on an aperture section of the clamping spring 37. Also, anotch section 37 a which is cut from an aperture end surface to apredetermined position is disposed on two positions in a longitudinaldirection of the clamping spring 37 such that the first lid element 34is compressed at a left-hand section of the clamping spring 37 in adirection of the base element 32 by this notch section 37 a, the secondlid element 35 is compressed in a direction of the base element 32 in acentral section, and the third lid element 36 is compressed in adirection of the base element 32 in a right-hand section.

The first clamping section 42 is formed by the first lid element 34, asection of the base element 32 which corresponds to it, and a left-handsection of the clamping spring 37 which is engaged to outsides of them.The second clamping section 43 (one clamping section) is formed by thesecond lid element 35, a section of the base element 32 whichcorresponds to it, and a central section of the clamping spring 37 whichis engaged to outsides of them. The third clamping section 44 (anotherclamping section) is formed by the third lid element 36, a section ofthe base element 32 which corresponds to it, and a right-hand section ofthe clamping spring 37 which is engaged to outsides of them.

Consequently, in order to connect two optical fibers 40, 41 by theoptical fiber connecting part 20 by using the optical fiber connectingtool 1 according to the embodiment which has the above explainedstructure, the optical fiber connector is fixed on the base 101. Thefirst open/close member 2 and the second open/close member 3 is movedforwardly in a direction of the optical fiber connecting part 20 byoperating a driving structure. The tip section of the first open/closemember 2 is inserted between the second lid element 35 of the connectingelement 31 and the base element 32 so as to resist the compressing forceof the clamping spring 37. The second lid element 35 is opened. The tipsection of the second open/close member 3 is inserted between the thirdlid element 36 and the base element 32 so as to resist the compressingforce of the clamping spring 37. The third lid element 36 is opened. Theoptical fiber 40 is inserted into the groove 32 a for alignment from oneside of the connecting structure 30 in advance such that its tip shouldbe disposed on the groove 32 a for alignment. The coating section isunder condition that it is clamped so as to be clamped between the firstlid element 34 and the base element 32. The coating section of theoptical fiber 40 is contained in the groove 32 b for containing acoating so as to be clamped and fixed by the first clamping section 42.The first clamping section 42 serves for an optical fiber fixingsection.

Consequently, the another optical fiber 41 is inserted along the groove32 a for alignment from another end of the connecting element 31. Thetip of the another optical fiber 41 is disposed between the second lidelement 35 and the base element 32 via the third lid element 36 so as tobe butt-connected to the tip of the optical fiber 40.

Consequently, the another optical fiber 41 is compressed in a directionof the optical fiber 40 so as to secure the butt-connecting force forboth of the optical fibers 40, 41. Under such a condition, the drivingstructure is operated so as to extract the first open/close member 2from between the second lid element 35 and the base element 32. Thesecond lid element 35 is closed by a compressing force of the clampingspring 37. The tip section of the optical fiber 40 (a naked opticalfiber 40 a which is exposed on the tip of the optical fiber 40) and atip section of the another optical fiber 41 are clamped between thesecond lid element 35 and the base element 32. The tip sections for theboth of the optical fibers 40, 41 are maintained under a butt-connectedcondition.

Consequently, after the second clamping section 43 is closed, a forcefor compressing the another optical fiber 41 in a direction of theoptical fiber 40 is released. Under such a condition, the drivingstructure is operated so as to extract the second open/close member 3from between the third lid element 36 and the base element 32. The thirdlid element 36 is closed by a compressing force of the clamping spring37. The coating section of the another optical fiber 41 is clampedbetween the third lid element 36 and the base element 32.

By doing this, it is possible to maintain the condition under which theoptical fiber 40 and the another optical fiber 41 are butt-connected viathe optical fiber connecting part.

In the optical fiber connecting tool 1 according to the presentembodiment which has the above explained structure, the first open/closemember 2 and the second open/close member 3 are operated independently,and the first open/close member 2 is extracted so as to close the secondlid element 35. After that, the second open/close member 3 is extractedso as to close the third element 36. By doing this, in a case in whichthe another optical fiber 41 is butt-connected to the tip of the opticalfiber 40, if there occurs a deformation on a tip sections of the both ofthe optical fibers 40, 41 due to the butt-connecting force, the thirdlid element 36 is still under an opened condition when the second lidelement 35 is closed. Therefore, it is possible to dispose such adeformation in a direction of the optical fiber 41; thus, the third lidelement 36 is closed after removing the deformation completely(otherwise mostly).

Therefore, there do not occur a case in which the both of the opticalfibers 40, 41 are clamped while a deformation is generated on the tipsections of the both of the optical fibers 40, 41, the loss increasesdue to bending the optical fibers 40, 41, and a stress is concentratedon the tip sections of the both of the optical fibers 40, 41; thus, theyare broken. Therefore, it is possible to eliminate the defectconnection; thus, it is possible to enhance the reliability greatly.

In FIG. 19 and FIG. 20, a third embodiment of the optical fiberconnecting tool according to the present invention is shown. In theoptical fiber connecting tool 45, a first open/close member 47 and asupporting member 48 are connected unitarily to an operating lever 46,and simultaneously, a second open/close member 49 is attached thesupporting member 48, and a pin 50 which is disposed on the supportingmember 48 is disposed in a long hole 51 which is formed on the secondopen/close member 49. The other structure is similar to that shown inthe above explained first and the second embodiments.

The member which is shown in the present embodiment realizes a similaroperability and an effect which are shown in the above explained firstand the second embodiments. In a case in which a newly installed opticalfiber is butt-connected to a tip of a pre-installed optical fiber, or ina case in which a tip of an optical fiber is butt-connected to a tip ofanother optical fiber, even if there is a deformation which is generatedon the tip sections for the both of the optical fibers due to thebutt-connecting force, the second lid element or the third lid elementare under opened condition when the first lie element or the second lidelement is closed. Therefore, it is possible to dispose such adeformation in a direction of the newly installed optical fiber or theanother optical fiber,; thus, the second lid element or the third lidelement 36 are closed after removing the deformation completely(otherwise mostly).

Therefore, there do not occur a case in which the both of the opticalfibers are clamped while a deformation is generated on thebutt-connected section of the both of the optical fibers, the lossincreases due to bending the optical fibers, and a stress isconcentrated on the tip sections of the both of the optical fibers;thus, they are broken. Therefore, it is possible to eliminate the defectconnection; thus, it is possible to enhance the reliability greatly.

Also, in the present embodiment, when the operating lever 46 is operatedin a direction (more specifically, a direction of the connectingstructure) of the optical fiber connecting part, it is possible to movethe first open/close member 47 and the second open/close member 49forwardly in a direction of the connecting structure simultaneously(regarding the second open/close member 49, more specifically, a rearend which faces to the tip which is inserted into the connectingstructure of the second open/close member 49 is compressed by theoperating lever 46 so as to be moved forwardly toward the connectingstructure). Coincidentally, when the operating lever 46 is operated in adirection so as to be separate from the connecting structure, the firstopen/close member 47 and the operating lever 46 are moved backwardlyunitarily so as to be separate from the connecting structure. Afterthat, after a time-lag, the pin 50 of the supporting member 48 contactsan end surface of the long hole 51 of the second open/close member 49.By doing this, the second open/close member 49 retreats in a directionso as to be separate from the connecting structure. Therefore, it ispossible to simplify the structure for operating the first open/closemember 47 and the second open/close member 49.

Here, in the above explained embodiments, an operation for closing theanother clamping section starts after closing the clamping section.However, the present invention is not limited to such a structure. It ispossible to adapt a structure in which the movement of the closing theanother clamping section is started (before completing the clampingoperation for the pre-installed optical fiber and the newly installedoptical fiber in the one clamping section) before completing the closingmovement of the one clamping section.

1. A method for connecting optical fibers through a connecting structurehaving first and second clamping sections using an optical fiberconnecting tool having first and second opening/closing member, themethod comprising: opening the first clamping section by inserting thefirst opening/closing member into the first clamping section and openingthe second clamping section by inserting the second opening/closingmember into the second clamping section; inserting a first optical fiberinto the first clamping section and inserting a second optical fiberinto the fist clamping section through the second clamping section so asto butt-connect a tip of the first optical fiber to a tip of the secondoptical fiber; extracting the first opening/closing member from thefirst clamping section so as to clamp peripheries of the first andsecond optical fibers; and extracting the second opening/closing memberfrom the second clamping section so as to clamp the periphery of thesecond optical fiber.
 2. An optical fiber connecting tool according toclaim 1, wherein an optical fiber fixing section which clamps thepreinstalled first optical fiber to a ferrule is disposed in a regionwhich is provided on the opposite side of the second clamping sectionthrough the first clamping section, so as to fix the pre-installed firstoptical fiber.
 3. The method of claim 1, further comprising: preparingthe second optical fiber for insertion by exposing the optical fiber inan end of a coated optical cable; inserting the exposed optical fiberand the coated optical cable; and butt-connecting a tip of the exposedoptical fiber of the coated optical cable to the first optical fiber byclamping the exposed optical fiber in the first clamping section andclamping a portion of the coated optical cable in the second clampingsection of the optical fiber connecting tool.
 4. The method of claim 1,further comprising: applying a compressive force on second optical fibertoward the first optical fiber; opening the second clamping sectionwhile maintaining the compressive force; releasing the compressiveforce; and closing the second clamping section.
 5. A method forconnecting optical fibers through a connecting structure having firstand second clamping structures using an optical fiber connecting toolhaving first and second opening/closing members, the method comprising:inserting a first optical fiber into the first clamping section in whicha first opening/closing member is pre-installed and inserting a secondoptical fiber into the first clamping section through the secondclamping section in which a second opening/closing member ispre-installed so as to butt-connect a tip of the first optical fiber toa tip of the second optical fiber; and extracting the firstopening/closing member from the first clamping section so as to clamp aperipheries of the first and second optical fibers; and extracting thesecond opening/closing member from the second clamping section so as toclamp a periphery of the second optical fiber.
 6. A method forconnecting optical fibers through a connecting structure having firstand second clamping sections using an optical fiber connecting toolhaving first and second opening/closing members, the method comprising:opening the first and second clamping sections by inserting the firstand second opening/closing members into the first and second clampingsection; inserting a second optical fiber into the first clampingsection through the second clamping section so as to butt-connect a tipof the second optical fiber to a tip of a first optical fiber which ispre-installed in the first clamping section; extracting the firstopening/closing member from the first clamping section so as to clampperipheries of the first and second optical fibers; and extracting thesecond opening/closing member from the second clamping section so as toclamp a periphery of the second optical fiber.
 7. A method forconnecting optical fibers through a connecting structure having firstand second clamping sections using an optical fiber connecting toolhaving first and second opening/closing members, the method comprising:inserting a second optical fiber into the first clamping section whichis opened by the first opening/closing member through the secondclamping section which is opened by the second opening/closing member soas to butt-connect a tip of the second optical fiber to a tip of a firstoptical fiber which is pre-installed in the first clamping section;extracting the first opening/closing member from the first clampingsection so as to clamp peripheries of the first and second opticalfibers; and extracting the second opening/closing member from the secondclamping section so as to clamp a periphery of the second optical fiber.8. A method according to claim 6, wherein the first optical fiber isfixed to a ferrule connected to the first clamping section.
 9. A methodaccording to claim 7, wherein the first optical fiber is fixed to aferrule connected to the first clamping section.
 10. A method forconnecting optical fibers through a connecting structure having first tothird clamping sections in which the first clamping section is disposedin a region on an opposite side of the third clamping section throughthe second clamping section, using an optical fiber connecting toolhaving first and second opening/closing members, the method comprising:opening the second and third clamping sections by inserting the firstand second opening/closing members into the second and third clampingsection; inserting a second optical fiber into the second clampingsection through the third clamping section so as to butt-connect a tipof the second optical fiber to a tip of a first optical fiber which isclamped by the first clamping section and pre-installed in the secondclamping section; extracting the first opening/closing member from thesecond clamping section so as to clamp peripheries of the first andsecond optical fibers; and extracting the second opening/closing memberfrom the third clamping section so as to clamp a periphery of the secondoptical fiber.
 11. A method for connecting optical fibers through aconnecting structure having first to third clamping sections in whichthe first clamping section is disposed in a region on an opposite sideof the third clamping section through the second clamping section, usingan optical fiber connecting tool having first and second opening/closingmembers, the method comprising: inserting a second optical fiber intothe second clamping section which is opened by the first opening/closingmember through the third clamping section which is opened by the secondopening/closing member so as to butt-connect a tip of the second opticalfiber to a tip of a first optical fiber which is clamped by the firstclamping section and pre-installed in the second clamping section;extracting the first opening/closing member from the second clampingsection so as to clamp peripheries of the first and second opticalfiber; and extracting the second opening/closing member from the thirdclamping section so as to clamp a periphery of the second optical fiber.12. A method for connecting optical fibers according to claim 1, whereinbutt- connection force is maintained between the first and secondoptical fibers before the clamp of the second optical fiber by thesecond clamping section.
 13. method for connecting optical fibersaccording to claim 5, wherein butt- connection force is maintainedbetween the first and second optical fibers before the clamp of thesecond optical fiber by the second clamping section.
 14. A method forconnecting optical fibers according to claim 6, wherein butt- connectionforce is maintained between the first and second optical fibers beforethe clamp of the second optical fiber by the second clamping section.15. A method for connecting optical fibers according to claim 7, whereinbutt- connection force is maintained between the first and secondoptical fibers before the clamp of the second optical fiber by thesecond clamping section.
 16. A method for connecting optical fibersaccording to claim 10, wherein butt- connection force is maintainedbetween the first and second optical fibers before the clamp of thesecond optical fiber by the second clamping section.
 17. A method forconnecting optical fibers according to claim 11, wherein butt-connection force is maintained between the first and second opticalfibers before the clamp of the second optical fiber by the secondclamping section.
 18. A method for connecting optical fibers accordingto claim 1, wherein the extraction of the second opening/closing memberfrom the second clamping section is started after the extraction of thefirst opening/closing member from the first clamping section iscompleted.
 19. A method for connecting optical fibers according to claim5, wherein the extraction of the second opening/closing member from thesecond clamping section is started after the extraction of the firstopening/closing member from the first clamping section is completed. 20.A method for connecting optical fibers according to claim 6, wherein theextraction of the second opening/closing member from the second clampingsection is started after the extraction of the first opening/closingmember from the first clamping section is completed.
 21. A method forconnecting optical fibers according to claim 7, wherein the extractionof the second opening/closing member from the second clamping section isstarted after the extraction of the first opening/closing member fromthe first clamping section is completed.
 22. A method for connectingoptical fibers according to claim 10, wherein the extraction of thesecond opening/closing member from the third clamping section is startedafter the extraction of the first opening/closing member from the secondclamping section is completed.
 23. A method for connecting opticalfibers according to claim 11, wherein the extraction of the secondopening/closing member from the third clamping section is started afterthe extraction of the first opening/closing member from the secondclamping section is completed.
 24. A method for connecting opticalfibers according to claim 1, wherein the extraction of the secondopening/closing member from the second clamping section is startedbefore the extraction of the first opening/closing member from the firstclamping section is completed.
 25. A method for connecting opticalfibers according to claim 5, wherein the extraction of the secondopening/closing member from the second clamping section is startedbefore the extraction of the first opening/closing member from the firstclamping section is completed.
 26. A method for connecting opticalfibers according to claim 6, wherein the extraction of the secondopening/closing member from the second clamping section is startedbefore the extraction of the first opening/closing member from the firstclamping section is completed.
 27. A method for connecting opticalfibers according to claim 7, wherein the extraction of the secondopening/closing member from the second clamping section is startedbefore the extraction of the first opening/closing member from the firstclamping section is completed.
 28. A method for connecting opticalfibers according to claim 10, wherein the extraction of the secondopening/closing member from the third clamping section is started beforethe extraction of the first opening/closing member from the secondclamping section is completed.
 29. A method for connecting opticalfibers according to claim 11, wherein the extraction of the secondopening/closing member from the third clamping section is started beforethe extraction of the first opening/closing member from the secondclamping section is completed.